PCB Technical - PCB circuit board reliability test method

PCB circuit board reliability test method

With the development of the times, PCB circuit boards play an important role in today's life. It is the foundation and highway of electronic components. In this regard, the quality of the PCB circuit board is very critical.

To check the quality of PCB circuit boards (Shenzhen Circuit Board Factory), a number of reliability tests must be carried out. The following paragraphs are an introduction to the test.

1. Ion contamination test

Purpose: Check the number of ions on the surface of the circuit board to determine whether the cleanliness of the circuit board is qualified.

Method: Use 75% propanol to clean the surface of the sample. Ions can be dissolved in propanol, thereby changing its conductivity. The change in conductivity is recorded to determine the ion concentration.

standard: less than or equal to 6.45ug.NaCl/sq.in

2. Stripping strength test

Purpose: To check the force that can strip the copper wire on the circuit board

Equipment: Peel strength tester

method:

Strip the copper wire at least 10mm from one side of the substrate.

Place the multilayer PCB sample board on the tester.

Use vertical force to strip the remaining copper wire.

Record power.

Standard: The force should exceed 1.1N/mm.

3. Chemical resistance test of solder mask

Objective: To check the chemical resistance of the solder mask

method:

Drop qs (quantum satisfactory) methylene chloride on the surface of the multilayer PCB sample.

After a while, wipe the methylene chloride with white cotton.

Check whether the cotton is stained and the solder mask is dissolved.

Standard: No dye or dissolution.

4. Hardness test of solder mask

Purpose: To check the hardness of the solder mask

method:

Place the PCB circuit board on a flat surface.

Use a standard test pen to scratch a certain range of hardness on the boat until there are no scratches.

Record the minimum hardness of the pencil.

Standard: The minimum hardness should be higher than 6H.

5. Solderability test

Purpose: To check the solderability of pads and through holes on the board.

Equipment: soldering machine, oven and timer.

Method: Bake the board in an oven at 105°C for 1 hour.

Dip solder.

categorically put the board to the soldering machine at 235°C, and take it out in 3 seconds, check the area of the solder pad.

Put the board vertically into the soldering machine at 235°C, take it out after 3 seconds, and check whether the through holes are immersed in tin.

Standard: The area percentage should be greater than 95. All through holes should be immersed in tin.

6. Withstand voltage test

Purpose: Test the withstand voltage capability of the PCB circuit board.

Equipment: Withstand voltage tester

method:

Clean and dry the sample.

Connect the multilayer circuit board to the tester.

Increase the voltage to 500VDC (direct current) at a speed not higher than 100V/s.

Keep it at 500VDC for 30 seconds.

Standard: There should be no faults on the circuit.

7. Glass transition temperature test

Objective: To check the glass transition temperature of the board.

Equipment: DSC (differential scanning calorimeter) tester, oven, dryer, electronic scale.

method:

Prepare a multilayer PCB sample, the weight should be 15-25mg.

The multilayer PCB sample was baked in an oven at 105°C for 2 hours, and then placed in a desiccator to cool to room temperature.

Put the multilayer PCB sample on the sample stage of the DSC tester, and set the heating rate to 20°C/min.

Scan 2 times and record Tg.

Standard: Tg should be higher than 150 degree Celsius.

8. CTE (Coefficient of Thermal Expansion) Test

Target: CTE of the evaluation board.

Equipment: TMA (Thermal Mechanical Analysis) tester, oven, dryer.

method:

Prepare a sample with a size of 6.35*6.35mm.

The multilayer circuit board sample was baked in an oven at 105°C for 2 hours, and then placed in a desiccator to cool to room temperature.

Put the multilayer circuit board sample on the sample stage of the TMA tester, set the heating rate to 10°C/min, and set the final temperature to 250°C

Record CTE.

9. Heat resistance test

Purpose: To evaluate the heat resistance of the board.

Equipment: TMA (Thermal Mechanical Analysis) tester, oven, dryer.

method:

Prepare a sample with a size of 6.35*6.35mm.

The multilayer PCB sample was baked in an oven at 105°C for 2 hours, and then placed in a desiccator to cool to room temperature.

Put the multilayer PCB sample on the sample stage of the TMA tester, and set the heating rate to 10°C/min.

Raise the temperature of the multilayer PCB sample to 260°C.